Object Detection Demo

Welcome to the object detection inference walkthrough! This notebook will walk you step by step through the process of using a pre-trained model to detect objects in an image. Make sure to follow the installation instructions before you start.

Imports

In [1]:
import glob
import numpy as np
import os
import six.moves.urllib as urllib
import sys
import tarfile
import tensorflow as tf
import time
import zipfile

from collections import defaultdict
from io import StringIO
from matplotlib import pyplot as plt
from PIL import Image

# if tf.__version__ != '1.4.0':
#   raise ImportError('Please upgrade your tensorflow installation to v1.4.0!')
/home/ubuntu/anaconda3/lib/python3.6/importlib/_bootstrap.py:205: RuntimeWarning: compiletime version 3.5 of module 'tensorflow.python.framework.fast_tensor_util' does not match runtime version 3.6
  return f(*args, **kwds)
In [ ]:
tf.__version__

Env setup

In [2]:
# This is needed to display the images.
%matplotlib inline

# This is needed since the notebook is stored in the object_detection folder.
sys.path.append("..")

Object detection imports

Here are the imports from the object detection module.

In [3]:
from utils import label_map_util

from utils import visualization_utils as vis_util

Model preparation

Variables

Any model exported using the export_inference_graph.py tool can be loaded here simply by changing PATH_TO_CKPT to point to a new .pb file.

By default we use an "SSD with Mobilenet" model here. See the detection model zoo for a list of other models that can be run out-of-the-box with varying speeds and accuracies.

In [4]:
# What model to download.
# MODEL_NAME = 'ssd_mobilenet_v1_coco_2017_11_17'
# MODEL_FILE = MODEL_NAME + '.tar.gz'
# DOWNLOAD_BASE = 'http://download.tensorflow.org/models/object_detection/'

# Path to frozen detection graph. This is the actual model that is used for the object detection.
# PATH_TO_CKPT = MODEL_NAME + '/frozen_inference_graph.pb'

# PATH_TO_CKPT = '/home/ubuntu/homeroot/carnd-capstone-repo/classifier/faster_rcnn_inception_v2_real.pb'
# PATH_TO_CKPT = '/home/ubuntu/homeroot/carnd-capstone-repo/classifier/faster_rcnn_inception_v2_sim.pb'
# PATH_TO_CKPT = '/home/ubuntu/homeroot/carnd-capstone-repo/classifier/ssd_inception_v2_real.pb'
PATH_TO_CKPT = '/home/ubuntu/homeroot/carnd-capstone-repo/classifier/ssd_inception_v2_sim.pb'

# List of the strings that is used to add correct label for each box.
# PATH_TO_LABELS = os.path.join('data', 'mscoco_label_map.pbtxt')

PATH_TO_LABELS = '/home/ubuntu/homeroot/carnd-capstone-train/data/udacity_label_map.pbtxt'

NUM_CLASSES = 4

Download Model

In [ ]:
# opener = urllib.request.URLopener()
# opener.retrieve(DOWNLOAD_BASE + MODEL_FILE, MODEL_FILE)
# tar_file = tarfile.open(MODEL_FILE)
# for file in tar_file.getmembers():
#   file_name = os.path.basename(file.name)
#   if 'frozen_inference_graph.pb' in file_name:
#     tar_file.extract(file, os.getcwd())

Load a (frozen) Tensorflow model into memory.

In [5]:
detection_graph = tf.Graph()
with detection_graph.as_default():
  od_graph_def = tf.GraphDef()
  with tf.gfile.GFile(PATH_TO_CKPT, 'rb') as fid:
    serialized_graph = fid.read()
    od_graph_def.ParseFromString(serialized_graph)
    tf.import_graph_def(od_graph_def, name='')

Loading label map

Label maps map indices to category names, so that when our convolution network predicts 5, we know that this corresponds to airplane. Here we use internal utility functions, but anything that returns a dictionary mapping integers to appropriate string labels would be fine

In [6]:
label_map = label_map_util.load_labelmap(PATH_TO_LABELS)
categories = label_map_util.convert_label_map_to_categories(label_map, max_num_classes=NUM_CLASSES, use_display_name=True)
category_index = label_map_util.create_category_index(categories)

Helper code

In [7]:
def load_image_into_numpy_array(image):
  (im_width, im_height) = image.size
  return np.array(image.getdata()).reshape(
      (im_height, im_width, 3)).astype(np.uint8)

Detection

In [8]:
# For the sake of simplicity we will use only 2 images:
# image1.jpg
# image2.jpg
# If you want to test the code with your images, just add path to the images to the TEST_IMAGE_PATHS.
# PATH_TO_TEST_IMAGES_DIR = 'test_images'
# TEST_IMAGE_PATHS = [ os.path.join(PATH_TO_TEST_IMAGES_DIR, 'image{}.jpg'.format(i)) for i in range(1, 3) ]

# TEST_IMAGE_PATHS = \
#     glob.glob('/home/ubuntu/homeroot/_downloads/anthony-sarkins/real_training_data/*/*.jpg')[::30] + \
#     glob.glob('/home/ubuntu/homeroot/_downloads/alex-lechner/udacity_testarea_rgb/*jpg')[::30]

TEST_IMAGE_PATHS = \
    glob.glob('/home/ubuntu/homeroot/_downloads/anthony-sarkins/sim_training_data/sim_data_capture/*.jpg')[::30] + \
    glob.glob('/home/ubuntu/homeroot/_downloads/alex-lechner/simulator_dataset_rgb/*/*.jpg')[::30]

def batches(l, n):
    for i in range(0, len(l), n):
        yield l[i:i + n]

# Size, in inches, of the output images.
IMAGE_SIZE = (15, 10)
In [9]:
with detection_graph.as_default():
    with tf.Session(graph=detection_graph) as sess:
        # Definite input and output Tensors for detection_graph
        image_tensor = detection_graph.get_tensor_by_name('image_tensor:0')
        
        # Each box represents a part of the image where a particular object was detected.
        detection_boxes = detection_graph.get_tensor_by_name('detection_boxes:0')
        
        # Each score represent how level of confidence for each of the objects.
        # Score is shown on the result image, together with the class label.
        detection_scores = detection_graph.get_tensor_by_name('detection_scores:0')
        detection_classes = detection_graph.get_tensor_by_name('detection_classes:0')
#         num_detections = detection_graph.get_tensor_by_name('num_detections:0')
        
        batch_size = 1
    
        for test_image_paths_batch in batches(TEST_IMAGE_PATHS, batch_size):
            images_np = []
        
            for image_path in test_image_paths_batch:
                image = Image.open(image_path)
        
                # the array based representation of the image will be used later in order to prepare the
                # result image with boxes and labels on it.
                image_np = load_image_into_numpy_array(image)
    
                images_np.append(image_np)
    
            images_np = np.array(images_np)
    
            # Actual detection.
            start_time = time.time()
            (boxes_all, scores_all, classes_all) = sess.run(
                [detection_boxes, detection_scores, detection_classes],
                feed_dict={image_tensor: images_np})
            duration = time.time() - start_time
            print('duration over {} images: {}'.format(batch_size, duration))

            for image_np, boxes, scores, classes in zip(images_np, boxes_all, scores_all, classes_all):
                # Visualization of the results of a detection.
                vis_util.visualize_boxes_and_labels_on_image_array(
                    image_np,
                    np.squeeze(boxes),
                    np.squeeze(classes).astype(np.int32),
                    np.squeeze(scores),
                    category_index,
                    use_normalized_coordinates=True,
                    line_thickness=8)
                plt.figure(figsize=IMAGE_SIZE)
                plt.imshow(image_np)
duration over 1 images: 1.8664307594299316
duration over 1 images: 0.03070068359375
duration over 1 images: 0.030642032623291016
duration over 1 images: 0.03043198585510254
duration over 1 images: 0.03178882598876953
duration over 1 images: 0.04493880271911621
duration over 1 images: 0.04508352279663086
duration over 1 images: 0.04506659507751465
duration over 1 images: 0.04496002197265625
duration over 1 images: 0.04538297653198242
duration over 1 images: 0.046713829040527344
duration over 1 images: 0.0460054874420166
duration over 1 images: 0.04600858688354492
duration over 1 images: 0.046024322509765625
duration over 1 images: 0.046044111251831055
duration over 1 images: 0.04656863212585449
duration over 1 images: 0.04594111442565918
duration over 1 images: 0.0460963249206543
duration over 1 images: 0.04610490798950195
duration over 1 images: 0.04577159881591797
duration over 1 images: 0.046353816986083984
/home/ubuntu/anaconda3/lib/python3.6/site-packages/matplotlib/pyplot.py:524: RuntimeWarning: More than 20 figures have been opened. Figures created through the pyplot interface (`matplotlib.pyplot.figure`) are retained until explicitly closed and may consume too much memory. (To control this warning, see the rcParam `figure.max_open_warning`).
  max_open_warning, RuntimeWarning)
duration over 1 images: 0.04587149620056152
duration over 1 images: 0.04637646675109863
duration over 1 images: 0.04596543312072754
duration over 1 images: 0.045941829681396484
duration over 1 images: 0.045967817306518555
duration over 1 images: 0.04633069038391113
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